Going way OT here...
Why do you use "apples vs oranges" as an example of two things that shouldn't be compared?
Just a learned response or do you feel comparing two skin encased, seed producing tree grow fruit whose juice is wildly used by itself to be a bad comparison?
It's just one of those things I've always wondered why people do it.
it's an idiom
idioms ought not to be analyzed too closely
i guess it's easier than "comparing the color green to a screwdriver' or 'comparing a ham sandwich to the inherent meaningless of life'